Properties of Safety Important I&C Systems and their Components - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 72

parameters, applied for representation of these
states. Selection of such compliance is performed
on the basis of signal receiver properties. For ex-
ample, for execution of protective action initiated
by command of the reactor protection I&C system
(dropping of all control rods into core that causes
emergency shutdown of reactor), outputs of reac-
tor group and individual control rod system are
transferred by this command and retained in active
logical condition that is complied with a lack of
current in circuits, connecting these outputs with
all control rod drives. In the absence of a command
of emergency protection, logical state of outputs
provides direct current in these output circuits.
Safety systems support features that perform
information functions of monitoring, warning, dis-
play, archiving and control functions of regulation,
locking, discrete and remote control described in
Chapter 1. As an example the automatic control
system of diesel-generator used at Ukrainian NPP
(see Belohin et al, 2010) can be given.
During power unit operation or in standby
modes, automatic control system of diesel-
generator:

In case of operational events, the automatic
control system of diesel-generator forms and is-
sues control signals, providing:

• Start-up of a diesel-generator by a com-
mand obtained from the safety protection
I&C system and operational personnel, in-
cluding required operations and further au-
tomatic mutual synchronization of rotation
speed of two diesel-generators, operating
into a total load.
• Automatic support of required parameters
of a diesel-generator during a long period
of time, operating at a full capacity, includ-
ing reill of the service tanks of fuel, oil,
coolant, etc.
• Execution of manual (remote) control
commands: changing of active and reac-
tive generator power, connection and dis-
connection of auxiliary equipment.
• Automatic emergency shutdown of a die-
sel-generator (with locking of the next
launch) in case of actuation of uninter-
ruptable protective means of technological
equipment (other protective means are dis-
connected in order that functions of safety
system support features had a priority over
equipment protection functions).
• Automatic shutdown of a diesel-generator
by a command obtained from personnel,
including operations, which provide avail-
ability of a diesel-electric unit for the next
start-up.
• Warning of personnel (indicating alarm)
about execution of start operation, opera-
tion at a capacity and shutdown.

• Supports Diesel: Generator in con-

stant readiness for start-up and fast load
acceptance.

• Provides periodic checks (testing) of each

diesel-generator at zero load and with a
load on the a unit electrical network (in-
cluding synchronization of shaft speed
with network frequency and change of gen-
erator reactive capability).

• Continuously controls technical state and

diagnoses operability failure of its own
components, adjacent peripheral equip-
ment and connecting lines, archives di-
agnostic results and transfers them to the
main control room for display and warning
of personnel about failures, which can lead
to the system unavailability for execution
of speciied functions.

• Continuous monitoring, archiving, dis-

play and register of parameters of a diesel-
generator, adjacent equipment, events and
conditions during operation of a diesel
generator.